Pertussis, caused primarily by Bordetella pertussis, is a contemporary public health problem in the US and worldwide. With >48,000 cases reported in the US in 2012, it is the least well controlled of the vaccinepreventable diseases, despite excellent coverage with acellular pertussis vaccines. While there are several hypotheses for these increases in clinical pertussis, such as increased public and medical awareness, enhanced diagnostic sensitivity and adaptation of the causal organism, it is clear that the acellular pertussis vaccines elicit protection of significantly shorter duration and diffeent type than previously used whole cell vaccines or recovery from past infection.For these reasons, the upcoming 11th International Bordetella Symposium, scheduled for April 2016 in Buenos Aires, Argentina, is particularly timely. These meetings take place on a three-four year cycle and are generally attended by 200-300 individuals (basic scientists, physicians, public health officials, vaccine manufacturers and representatives of regulatory agencies) from multiple countries; this level of participation reflects enthusiasm of the international Bordetella Research Community for this event. The major topics of discussion (see preliminary program) at this include: pertussis epidemiology and pathogenesis, immune responses and mechanisms of clearance in natural disease and following vaccine (in animals and humans) and B. pertussis strains not expressing virulence factors/vaccine antigens. Since there appear to be multiple factors (such as disparate immune response from natural disease, emergence of circulating strains not expressing vaccine antigens and possible transmission from asymptomatic hosts) contributing to the resurgence of pertussis, this meeting will provide an ideal forum for discussion of these possibilities and how to deal with the problem definitively. Thus the final session as round table discussion and consensus building exercise will be an important culmination/product from this special event with participants representing relevant areas of expertise for identifying solutions and next steps.